1. Field of the Invention
The present invention relates to an apparatus for filling containers each with a specified amount of liquid such as flowable food.
2. Description of the Prior Art
Examined Japanese Patent Publication No. 26550/1984, for example, discloses such an apparatus which comprises a tubular nozzle body, a damper attached to the lower end of the nozzle body and movable upward and downward, a spring suspending member fixedly disposed in an upper portion of the nozzle body, a coiled spring suspended from the suspending member, a member connecting the lower end of the spring to the free end of the damper, and a resistance member fixed to the connecting member and positioned below the coiled spring for offering resistance to a liquid flowing down.
When the liquid is forcibly charged into the apparatus, the pressure of the liquid acting on the damper opens the damper against the force of the spring. The liquid pressure acting on the resistance member adds to the damper opening force, opening the damper to a greater extent and consequently permitting the nozzle body to discharge the liquid more rapidly. The rapid flow of the liquid precludes occurrence of air bubbles due to stirring of the liquid to assure a high-speed filling operation.
Despite the above advantage, the conventional apparatus has the following problem.
The spring force, if increased, makes the damper difficult to open, whereas a lower spring force renders the damper difficult to close. It is therefore difficult to adjust the spring force. Especially when the liquid to be filled contains a fibrous substance, fibers become lodged in the pivoted portion of the damper, making the damper no longer openable or closable smoothly.
The above problem may be overcome by forcibly opening and closing the damper with some actuator without resorting to the force of the spring. However, the damper must then be opened simultaneously with the feed of the liquid to the nozzle body, but this is difficult to realize. Further when the damper is quickly closed with the actuator, the resulting impact is likely to cause damage to the portion of the apparatus including the damper.